Polymers of formal esters



Patented Mar. 3, 1953 UNITED STATES PATENT OFFICE POLYMERS F FORMAL ESTERS William F. Gresham, Wilmington, Del., assignor to E. I. du Pont de Nemours and Company, W11- mington, Del., a corporation of Delaware No Drawing. Application December 13, 1949, Serial No. 132,790

6 Claims. (Cl. 260-783) 1 This invention relates to a process for the preparation of oxygenated organic polymers and more particularly to polymers obtained from linear formals. This application is a continuation-in-part of U. S. Patent No. 2,382,938, patented August 14, 1945 and U. S. Application Serial No. 571,957, filed January 8, 1945, now abandoned.

An object of the present invention is to provide new polymeric compounds and processes for their preparation. Another object is to provide new polymeric compositions from polymerizable linear formals. Yet another object is to provide a process for the polymerization of linear formals. Still another object is to provide mixtures or interpolymers of linear formals with homologous polymerizable compounds, or with cyclic and alicyclic alkylene oxides and the like.

Other objects and advantages of the invention will hereinafter appear.

It has been found that linear formals containing two or more functional groups,such groups being defined for the purpose of the specification as hydroxyl groups (OH) and formal groups (-OCH2O), can be reacted to give products having a wide range of physical and chemical properties by contacting them with a suitable catalyst under properly controlled conditions. These products will be defined as polymers, which term will include the chemical combination of at least two polyfunctional linear formals as well as the intermediate products resulting from the polymerization which contain at least two glycol "residues; e; g. the residues The linear formals containing two or more functional groups which may be polymerized in accord with the invention include, for example:

- methyl hydroxyethyl formal,

CH30CH20(CH2):OH ethyl hydroxyethyl formal.

C2H5OCH2O(CH2) 20H propyl hydroxyethyl formal,

lbutyl hydroxyethyl formal,

C4Hc0CI-I2O(CH2) 20H methoxyethyl hydroxyethyl formal,

.CHaO(CH2) 2OCH2O(CH2) 20H .methyl-, ethyl-, propyl-, butyl-, and methoxyethyl-hydroxypropyl formals, which may be illustrated by the formula, ROCI-IzOCsHcOH, in which the R group is respectively methyl, ethyl, propyl, butyl, methoxyethyl, etc., and the higher alkyl hydroxyalkyl formals such as are disclosed in the copending application of Sussman et al., S. N. 288,587, filed August 5, 1939, now abandoned, di(fi-hydroxyethyl) formal,

(HOCHzCHzO) zCHz dip-(hydroxyethyh methoxy ethane,

(HOCHzCHzOCI-IzO) 2C2H4 and die- (hydroxyethoxy) methoxyethyl formal, (HOCHzCI-IzOCI-IzOCI-IzCHzO) zCHz and the higher homologues HOCH2CH2(OCH2OCH2CH2) eOH where a: is greater than 3; 1,2-di(isobutoxymethoxy) ethane,

C4H9OCH2OCH2CH2OCH2OC4H9 and compounds of the general type ROCHzOCHzCHzOCI-IzOR in which R is a lower alkyl group such as are described in U. S. Patent 2,350,350 of W. S. Gresham, patented June 6, 1944, and which are prepared by the polymerization of the reaction product from vicinal glycols and aldehydes in the presence of an acidic catalyst, which catalyst is destroyed before separating the product. Polyformal esters of polybasic acids are likewise polymerizable, e. g. the (methoxymethoxylethanol esters of oxalic, malonic, diglycolic, succinic, glutaric, adipic, pimelic, and the higher aliphatic dibasic acids as well as phthalic acid and generally acids having the formula,

CnHZn (COOH) 2 Polymers may likewise be obtained from such compounds as p-(methoxymethoxy) -ethyl(methoxymethoxy) acetate,

CHaOCI-IzOCI-IzCOOCHzCHzOCHzOCI-Ia and similar fi-(alkoxymethoxyethyl) esters of alkoxy methoxy carboxylic acids and from di- (p-methoxymethoxy) ethanol esters of the dibasic acids,

cnaocn ocmcmooc (CH2) ,coocmcmocnzocm in which a: is greater than one, and the diQS- methoxymethoxy)ethyl esters of 1,1-di-(carbomethoxymethoxy) methane, these esters being obtainable by ester interchange of 1,1-di- (carbomethoxymethoxy)methane,

CH2 (OCHaCOOCI-Ia);

disclosed in the copending application of Loder et al., U. S. Patent No. 2,364,455, patented December 6, 1944, which describes the preparation of the acetals of hydroxy aliphatic acids and their esters by the interaction of hydroxy aliphatic acids or their esters with aldehydes in the presence of an acid catalyst, and the (alkoxymethoxy) ethanols, RCH2OCH2CH2OH, which are prepared by the reaction of vicinal glycols with acetals in the presence of an acidic catalyst, the ester interchange being carried out in the presence of an alkaline catalyst, such as sodium methoxide. Polymers of the latter types will have terminal reactive groups. Low molecular weight polymers of the linear formals of the invention can also be converted to higher molecular weight polymers by the process of the invention.

The polymerization iseifected at temperatures ranging between -80 and +300 C. and prefer- .ably between 0 and 150 C. Atmospheric, subor superatmospheric pressures may be used, and

.if the last, pressures may range between 1 and .1000 atmospheres or higher.

Normally excellent results are obtained at or about atmospheric pressure. If desired, the temperature of the reaction, especially when polymerization is carried out at the boiling point of the reaction mixture, may be controlled by varying the pressure on the boiling reactants.

It has been found advantageous to effect the polymerization in the presence of an acidic type catalyst such, for example, as sulfuric. acid, phosphoric acid, hydrochloric acid, hydrofluoric acid (alone or with BFs), boron fluoride (including its complexes with water, acids, esters, alcohols, and the like), paratoluene sulfonic acid, camphor sulfonic acid, and other acid catalysts of this general nature. Friedel-Crafts type catalysts other than BFs may be used, such as A1013, .AlBI3, FeCla, and so'forth, as well as inorganic acids generally and their acid salts such as sodium acid sulfate, sodium acid phosphate, and so forth.

The catalyst may be supported or not on inert supports such as charcoal, silica gel (which alone is a catalyst for the reaction), kieselguhr, and so forth. Concentrations of BFa, H2SO4, and similarly strong acid catalysts may be extremely low, less than 0.1%, and amounts downtoas low as10.001% of these strong acid catalysts have .beenfound suificient to give polymers although highconcentrations of the catalyst even equal to or greater than the weight of the linear formal are likewise satisfactory.

The reaction is preferably continued approximately to equilibrium in order to effect the polymerization, or, if desired, reaction products are separated to force the reaction in one direction and until the molecular weight distribution wanted in the final product is attained. The reaction is generally continued for from 0.5 to hours at temperature ranges between 25 and 150C. and from l'to 10 days at temperatures below- 0 C., although shorter or longer reaction base, such as ammonia, alkali metal, and alkaline earth metal hydroxides, carbonates, alkoxides, and so forth or an organic base,suchas pyridine, dimethylamina'andthe like. These bases are added in sufficient amounts to neutralize the catalyst when acid catalysts are used, and the unconverted reactants may be removed, continuously, if desired, by distillation under reduced pressures. As soon as the catalyst has been neutralized, the reaction ceases. The neutralized catalyst may be filtered off and the, polymerized product which remains treated for the .recovery of the polymers.

The linear formals may be polymerized in various ways. The polymerization may be carried out by treating the monomer and catalyst in the presence or absence of a solvent for the monomer and polymer and for this type of polymerization such solvents as 1,4-dioxane, benzene, and toluene may be used.

The polymerizable linear formals above re-- ferred to can be converted to products having a wide range of physical and chemical properties, by simultaneous polymerization in contact with homologous polymerizable compounds of v.the cyclic and alicyclic alkylene oxides. Compounds so obtained are in many. instances interpolymers, although not necessarily so. For the preparation of such compounds, the polymerizable linear formals can be polymerized with the epoxides, such as ethylene oxide, 1,2- and .1,3-propylene oxides, tetramethylene oxide, isobutylene oxide, and their isomers and metamers. Interpolymers may likewise be made by polymerizing one linear formal of the class specified with another linear formal of the class. For example, interpolymers can be made by the simultaneous polymerization, in contact, of (methoxymethoxy) ethanol with di(beta-hydroxyethyl) formal, any amount of the (methoxymethoxy) ethanol from 1 to 1000 per part of thedi(beta-hydroxyethyl) formal may be used.

The polymerization of polyfunctional linear formals does not ordinarily produce a single polymeric product, but generally 'gives'two or more such products, the distribution of polymers present being determined inter alia by the temperature of the reaction and the type andconcentration of catalyst employed. It may be desired to obtain from these productsagiven polymer and this can be effected by carrying out the polymerization by a process wherein a portionof the desired product is removed from the reaction zone and the undesired products returned to that zone together with the linearformal being polymerized.

Examples will. now' be givenillustratingembodiments of the invention, but it will be understood that it will not be limited by the details thereof. Parts are by weight unless otherwise indicated.

Example 1.A reaction mixture consisting .of 1060 parts of (methoxymethoxy)ethanol and 3 parts of sulfuric acid was heated on awater bath at 40-50 C. and 28 mm. until 386 parts of lower boiling products were collected in a Dry-Ice cooled trap which was placed between the reaction vessel and a vacuum pump. The sulfuric acid was neutralized with a 28% 'solution'of sodium methoxide. Materials boiling .up to approximately 75 C./3 mm. were removed. This gave 559 parts of a water-white viscous liquid polymer which was soluble in water, benzene and methanol-hydroxyl No. 312; density at.25 C., 1.160; refractive index at 25 0., 1.5000; estimated molecula weight in boiling benzene, 320. 1

Example 2.A reaction mixture, prepared by careful addition of 4 parts of sulfuric acid to573 g. of '(methoxymethoxy) ethanol, was processed under conditions setfo'rth in Example 1 and until 152 parts of lower boiling materials collected in the Dry-Ice trap. Subsequent to neutralization of the catalyst with sodium methoxide dissolved in methanol, distillation under 3 mm. pressure, carried out until the head temperature reached 115 C., gave 216 parts of a colorless viscous liquid polymer-hydroxyl No. 326; density at 25 C., 1.080; refractive index at 25 C., 1.4480. The polymer was soluble in water, benzene and methanol.

Example 3.-A mixture consisting of 416 parts of (methoxymethoxy) ethyl (methoxymethoxyT- acetate, CH3OCHzOCI-IzCOOCH2CH2OCH2OCH3, and 1 part of sulfuric acid was heated on a water bath under 40 mm. pressure until 115 parts of methylal .was removed. The catalyst was neutralized with a slight excess of anhydrous ammonia. Removal of excess ammonia at 2 mm. and 100' C. gave 300 parts of a viscous liquid polymer that was only slightly soluble in watersaponification No. 384; refractive index at 25 C., 1.4580.

Example 4.-To 42.5 parts of di(methoxymetho x y e t h a n e, CHsOCI-IzOCI-IzCI-IzOCHzOCHs, cooled in an ice bath was added 0.1 part of boron fluoride. The reaction mixture so prepared, was distilled until 18.8 parts of methylal had been collected. The product 'was treated with anhydrous ammonia to destroy the catalyst, dissolved in benzene and the benzene filtered to remove inorganic precipitates. Removal of benzene under reduced pressure, finally to 1 mm. and 100 C., gave 21.5 parts of a viscous liquid polymer which was soluble in water.

Erample 5.-A mixture of 623 parts of di- (methoxymethoxy ethyl) adipate and 0.09 part of concentrated sulfuric acid was heated under reduced pressure at a pot temperature of 170 C. until 14 parts of methylal were removed. After the addition of 0.1 part of NaOH in 2 parts of water, the reaction mixture was topped to remove water and then filtered. The polymer, a pale yellow, viscous liquid, was soluble in benzene and insoluble in alcohol and water. Molecular weight in boiling benzene 728.

The compounds prepared in accord with the invention may be employed for a large number of uses. The lower molecular weight polymers and/or solutions of the higher molecular weight polymers in water or other suitable solvent may be employed in the uses designated below which require solubilized agents; e. g., as solvents, extractors, fungicidal uses, and so forth. The higher molecular weight polymers may be used as produced or in solution in many of the designated uses, such, for example, as those described under cosmetics, elastomers, leather and related, materials.

In the textile industry, solutions of the polymers may be used as sizers for nylon, rayon, wool, silk, and cotton; as a size lubricant; or as a textile softener to improve hand, either as such or after treatment, e. g., after shrink-proofing. The polymers may also be employed as: plasticizers for artificial yarns; spinning assistants; mercerizing assistants; and modifying assistants for dye receptivity. They may be used for improving dye fastness; increasing cleaning, wetting, dispersing, spreading, emulsifying, levelling and dyeing capacities; fulling, after treating, washing, and carbonizing; cross-linking (especially hydroxy-containing) polymers; and may be used to prevent mildew, rot and fungi infestation; improve creaseproof, crushproof and crinkleproof characteristics of textiles; and to give a permanent textile finish. r

In the paint, varnish, polish and finishing industries, the polymers may be used in the preparation of furniture and shoe polishes; as emulsions or solid waxes; as hot melts with other solids, as the esters of methacrylic acid, hydrogenated castor oil, polyvinyl alcohol resins, methylol ureas, etc.; as dressings for belts as non-slip, anti-squeak and as a general preservative. They are useful as, ingredients in adhesives; dispersing, spreading, binding, and wetting agent in paint, pigments, and lakes; as an agent to prevent livering in paints; as a substitute for alkyd varnishes and resins; as a termite repellent in lacquers and paint; as an ingredient of slow drying lacquers; as a binder for ceramic glazes-to be subsequently fired; and

as wax and resin plasticizers generally.

In the preparation and use of ink the polymers described may be employed in the print roll composition; as an addition agent to the ink or to the roll to improve offsetting qualities, both in the offset process and to prevent offset or smear between sheets; as an emulsifying, spreading, binding, dispersing, agent, tack and viscosity improver, adhesion assistant, and livering preventive in printing inks; as a suspending medium for printing pastes; as in ingredient in duplicators, either in the ink or in the pad; and as a gloss improver.

The polymers are likewise useful in the paper industry as a paper size for waxing to make paper and cardboard oilproof and airproof; for improving wet strength of paper, as a substitute for natural waxes in carbon paper, as a paper plasticizer, coating for paper condensers and insulators, and for transparentizing paper.

In the rubber field the polymeric products may be used as preservatives, rubber plasticizers, plasticizers for artificial rubber-like materials, protective coating for rubber, as an ingredient for incorporation with either rubber or artificial rubber to make them resistant to oil and gasoline, to improve low temperature flexibility, as an antioxidant, ozone resistant, and for making artificial rubber-like materials by reacting the polymers with glue.

Leather and related materials may be improved by these polymers as their use renders such ma terials fat-resistant. Furthermore, they may be used in fur mordanting, as a tanning agent, as an ingredient to make leather soft and pliable, as a preservative for footwear, ornaments, leather belting, etc., and as a "Fabrikoid softener and coating agent.

These polymeric compounds have many important uses in the cosmetic industry as, for example, an emulsifying agent and as an ingredient in creams, lotions, lathers, hair dressings, etc.; are adaptable for use in the preparation of antiseptic soaps and as a binder for hand, abrasive, and toilet soaps; as an invisible glove component for protecting hands and face; as a. permanent wave preparation; and as a watersoluble base for ointments and salves.

Chipping, corrosion and scratching of glass, china, metals, stone, wood, and like materials may be inhibited by coating with these polymers and they may also be used on electrical insulators or as an ingredient in electrical insulator compositions; as an impregnant for hood lacings, leaf springs, window channel linings, water pump stuffing, shoe sole liners, etc., and especially as a lubricant 0r anti-squeak. The polymers emam 7 maybe nse'dzas interlinersz.forisafetycg1ass,:.and Polaroid glass interlayers; wrapping .,.-mater.ia1s tor rfoods, ;:b1;ead,ffr.uit, -.etc,; t-as .za .Wcoating "iOl' fruits. vegetables; cggsfifoods etc. to :be .applied lasiatmeltr or solution tozthe comestibles against air and moisture; .for the preparation of translucent scrcens;.==as.an.interpolymer with ethylene oxide, ethylene, vinylwcompounds ori rubberrlike ,polymer forming :materials; ;and as a 2plastic .emulsion.-.ingredient.

"The ,po1ymers may the likewise 1 employed ..,as plasticizers -for cellulose and..cellulose deriva- .tives; .for.rshrinkproofing acetate silk? .as, aseal- .ingi agent a for ,oil :and gas wells drilling .mud ingredient .to {control 1:.thixotropy, settling, .etc.; grinding-raid in. clinker .cementfiotation agent in ore..treating,improving.root growth, .as an in- .qgredient in-rinsect and, iungicidal. sprays either as adhesive .orw active agent; as a water soluble swire and metal lubricant; as a bonding agentifor rfinelymdivided materialsyionsealing wounds in ltreesu-asfa water. soluble: ingredient for addition to artistsi, crayons; as. a ,surface tension depresasant. for. use with other. surface active materials; as a iplasticizeip for gluecasein,,proteins. v elatin,

;cork,--etc. They maybeemployed as substitutes .for glyce 'ine. foots. in electroplatingv baths as .a cutting aid in. metal turning; mandsas a metal cleaner. .The polymeric productsv likewise may be .1. incorporated with .greases Ito .improve Zlubrication, consistency, and the viscositycoefiicient; as

ha gas absorbent; poison gaspollector; .dust col- ..lector f in .air .con'ditioning; emulsifying agent in lemulsion polymerizationhas: anoaddition. to .cel- .lulose: filmstto; rendercthemmonecurlin ;..;and.2as

an,.additiomtotcellulose.nitratelandccllulose;ace-

tate to. make, non=corrosive as,.a binder' fonabmsive wheels which completely volatilizes .on ffiring; 1, and..a.s. an. ingredient. in self esealing L. tubes andtires.

"I. claim:

l- 1. Apolymer. of. (alkoxymethoxy) ethel" ester of an alkanedioic acid.-

..2...A .polymer of di(beta-methoxymethoxy) ethyl. diglyco'late.

3.;A polymer .bf .idii'betamethoxymethoxy) ethyl adipate.

45A polymer of beta- (Inethoxymethoxy) ethyl (me'thoxymethoxy) acetate.

15. A, polymer .of "an (alkoxymethoxy) :"ethyl esterjof an .acidofthe igroup' consistingbf alkoxymethoxyalkanoic, alkane dioic, di'glyc olic" and 'phthalic. acids.

C6.v A polymer "of (alkoxymethoxy) "ethyl ester 'of an alkoxyme'thoxyalkanoic acid.

WILLIAM F. GRESHAM.

REFERENCES CITED .The following references. are .of record.in1 the .file of .this :patent:

YUNITED! STATES'..PATENTS Number Name Date 2,129,694 'Izard Sept." 13, 1938 2,279,882 -DAle1io "Apr. 14, 1942 

5. A POLYMER OF AN (ALKOXYMETHOXY) ETHYL ESTER OF AN ACID OF THE GROUP CONSISTING OF ALKOXYMETHOXYALKANOIC, ALKANEDIOIC, DIGLYGOLIC AND PHTHALIC ACIDS. 